Stencil-sheet.



No Drawing.

"an snares manner onnicn ALBER'I IB.'DICK, GEE LAKE FOREST, ILLINOIS, ASSIGNOR TO A. B. DICK COMPANY, OF

CHICAGO, ILLINOIS,'A CORPORATION OF ILLINOIS.

STENCIL-SHEET.

To all whom it may concern Be it known that I, ALBERT B. DICK, a

.citizen of the United States, and a resident of Lake Forest, in the county of Lake, in the State of Illinois, have invented certain 'new and useful Improvements in Stencil- Sheets, of which the following is a specification.

My invention relates particularly to stencil sheets of the type commonly used for autographic and typewriting duplication. In such sheets the characters'are formed by pressure, 11. e. that of a stylus or the type of a Writing machine, and through such characters ink is passed to the impression sheet underlying such stencil sheet.

Also the invention concerns particularly that type of such stencil sheets in which are employed a base of open porous material, such as the Japanese paper commonly known as yoshino, and a colloidal coating for such base such as coagulated protein. One difficulty which has been experienced with such stencil sheets is due to the drying out of the coating which interferes to some extent with the process of stencilization. Under my invention I provide a coating of a char acter resisting the tendency to dry out from any cause such as evaporation.

In carrying out the invention the principal ingredients employed are gelatin, a tempering-agent such as sugar or glycerin or both, a solvent such as acetic acid or alcohol or both, water, a coagulant preferably of the chromic class such as potassium dichromate, and finally Turkey red oil. A practicable formula for use in compounding such a coating (but to which the invention is not limited) is elatin 27 lbs, granulated sugar 13 lbs., acetlc acid 3 lbs., water 79 lbs, glycerin 79 lbs., denatured alcohol 132 lbs, po-

tassium dichromate solution 21 lbs, Turkey red oil 20 lbs. To this may be added, if

desired, a suflicient quantum (for example,

3 lbs.) of a suit-able color solution. These ingredients may be combined in any suitable manner and in any desired order. For example, I prefer to break the gelatin into pieces of convenient size and to dissolve these in a solvent of acetic acid, to which a portion of the water may be added. Simi- Specification of Letters Patent.

Application filed" February 7, 1914. Serial No. 817,848.

Patented June 23, I914.

larly, the potassium dichromate is preferably used in crystal form, the solution thereof being produced by the admixture of .a suitable part of the water ingredient there-' with. The whole composition, when finally combined, may desirably be maintained at a low heat and the sheets of the yoshino immersed therein or drawn over the surface thereof, excess composition thereon being removed by passing the sheet over a straight edge or wire. To cure the sheet so coated'it is then hungin the 1ight,thereby facilitating the coagulation of the protein and consequent completion of the process. The Turkey red oil in the composition serves to maintain the coating in usable condition for a substantial length of time, resisting the tendency of such coating to dry'and become brittle and hard. Also by its use it is possible to obtain a stencil-sheet having a coat ing of the desired softness but Without the stickiness which characterizes a coating of the same softness. obtained by the free use of glycerin. In addition, I have found that Turkey-red oil is to considerable extent ink- -repellent. Its use, therefore, guards against lated'protein combined with Turkey red oil and a suitable tempering agent, substantially as described.

4. A stencil sheet adapted for stencilization by pressure, comprising a base of open porous material impregnated with a composition including protein, a coagulant and Turkey red oil, substantially as described.

5. A stencil sheet adapted for stencilization by pressure, comprising a base of open water, alcohol, glycerini potassium dichro- 10 porous material impregnated with a composition including protein, a coagulant, Turkey red oil and a-tempering agent, substan-- tially as described.

6. A stencil sheet adapted for stencilization by pressure, comprising a base of open porous material impregnated with a composition including gelatin, sugar, acetic acid,

mate and Turkey red oi This specification signed and witnessed this 4th day of February, 1914.

, ALBERT B. DICK.

Witnesses W. G. ARNOLD, W. A. WATERBURY. 

